The nutritional value of animal bones is well known by nutrition experts, yet in spite of their calcium, phosphorus, iron, and trace mineral content, such materials have heretofore been used almost entirely in animal and poultry feeds, rather than as food intended for human consumption.
Accordingly, one important object of the present invention is to provide method and apparatus suitable for producing a low-fat, colloidal or emulsive product having a high nutritive content of protein, calcium, phosphorus, iron, and other minor elements which is useful and desirable for human consumption.
In this respect, the present invention contemplates a continuous, pressure-cooking operation in which the bones are first reduced to particle form and combined with water to produce a slurry which is introduced into the lower end of a cooking tower. As the slurry passes through the cooking tower, it is subjected to intense pressures from the column of liquid thereabove and to high temperatures so that the bone particles are softened and further disintegrated, ultimately forming a colloidal suspension or emulsion which is drawn off adjacent the upper end of the tower. From there the product may be further processed in a variety of ways, if desired, including straining out all bone particles to be utilized in dry form, saving the liquid to be used as a broth, or collecting the emulsion itself and utilizing it in connection with soups and the like.
During its passage through the cooker, the slurry is also subjected to turbulence in the lower end of the tower which promotes further disintegrating of the bone particles, and due to the higher specific gravity of such particles relative to other constituents of the slurry, the particles tend to remain down in the turbulent section of the tower to be exposed to the disintegrating forces in that area while the lighter fraction rises to the top to be drawn off. Preferably, the turbulence may be accomplished by a tangential recirculating system, combined with strategically located fragmenting bars and projections which are impinged by the bone particles during their swirling movements and other travels in the lower tower section.